A principal precipitator of much of this was, of course, the mere presence of Barack Obama on the Democratic ticket, and the efforts by his opponents to negatively exploit his name, parentage, and upbringing.

To measure how cleaning performance changes over time, we tested the Friedrich C-90B plate-type electrostatic precipitator, or EP, air purifier and the Whirlpool Whispure AP45030S and IQAir HealthPro Plus HEPA-filter models.